Creator: None (system-internal Symbol).
This Tag decides which symbols are considered active for the purpose of activating Rules.
Create a Tag with this symbol targeting another symbol to signal that symbol with a given weight and (optionally) comment.
You can also target another Tag instead of a symbol, in which case the symbol of that Tag is used instead.
Newer instances of this Tag with the same comment overwrite older ones. Using !nullify on this Tag causes it to be ignored, but does not set the signal weight back to 0 if there are still other instances of this Tag with the same Symbol and comment as the deactivated one.
Note about the way Rules work: Each dependency of a Rule is satisfied only if a signal exists that matches the dependency. The dependency matches if the Symbols are the same and the filter string of the dependency is either not required, or is equal to the comment of the !set_signal_weight Tag. The weight of an active dependency is the product of the !set_signal_weight Tag's weight and the dependencies weight. The weights default to 1.0 if they are not given.